Anthracnose

  • Symptoms

    • Leaves develop irregular water soaked or blackish green blotches that eventually turn black or brown. The blotches develop from the margin inward and are usually limited only by the midvein. Leaflets curl toward the blighted area. Ash anthracnose symptoms develop in mid spring and are often followed by sudden premature drop of affected leaflets
  • Management

    • Remove and destroy infected twigs and branches during dormancy. Rake and remove fallen leaves in the autumn. Apply chlorothalonil, mancozeb, or thiophanate methyl + mancozeb as the young leaves and twigs are forming to protect them against initial infections. Continued applications are required until the weather becomes dry and daily temperatures average above 65 F

Decline

  • Symptoms

    • Tree growth slows. Tufts of numerous branches form. Branch dieback progresses until much of the tree is dead.
  • Management

    • Protect the tree from as many stresses as possible..

Ganoderma Root Rot

  • Symptoms

    • Branches dieback as a root rot develops. A very distinctive shelf-like fungus grows on the wood annually singly or in overlapping clusters. These shelves are brown to reddish brown on top with a cream to white margin and may become 14 inches across. The upper surface may appear to have been varnished.
  • Management

    • The appearance of the fungus on the tree is the last sign that the tree is severely diseased. Remove the tree immediately if it is in a location where falling limbs or the falling tree poses a threat to life or property.

Laetiporus Root Rot

  • Symptoms

    • The bark is slightly depressed and cracked in areas on trees with dying limbs. Infected trees are very prone to wind breakage. Massive clusters of bright, sulfur-yellow to salmon to bright-orange, shelf-like fruiting structures that turn white with age initially form in the summer or autumn on the wood of the tree but fall off during the winter. The underside of the fruiting structure has tiny pores in which the spores are formed. New shelves form on the wood the following summer and autumn. Fruiting occurs long after most of the damage has been done.
  • Management

    • Remove the tree at the first sign of infection since it poses a very serious treat to life and property.

Rust

  • Symptoms

    • In the spring along the East Coast, yellow-orange spots form on the leaves of white and green ash. Leaves become distorted as orange fungal fruiting structures form on the underside of leaves and on petioles. Cankers form on twigs, and trees can be defoliated prematurely. The spores formed on ash blow to and infect Spartina (cordgrass) in salt marshes where the fungus overwinters
  • Management

    • Apply chlorothalonil or mancozeb in the spring to protect young leaves and twigs of trees usually found with the disease. Trees usually free of the disease should not be sprayed.

Yellows

  • Symptoms

    • Twig and trunk growth slows to less than half of the growth rate before infection. Bud break is 1 to 2 weeks earlier than normal. Foliage appears to be in tufts because of the very short internodes. Witches' brooms may form. Leaves may be yellow and smaller than normal. Scattered branches die during the winter. Water sprouts form along branches or at ground level.
  • Management

    • Leafhoppers and spittlebugs carry the pathogen. Remove infected trees.

 

Anthracnose on an Ash Tree

 

Mosaic on an Ash Tree